The Senate Finance Committee's hearing to consider President Barack Obama's nominee to run the IRS became the latest casualty of procedural sparring on Tuesday.

Republicans invoked the Senate's rule against holding committee meetings beyond the first two hours of the Senate's day with respect to the Finance panel's nomination hearing on John Andrew Koskinen to be commissioner of the IRS.

"The other side of the aisle, the Republican Party, has objected, as is their right under the Senate rules," Chairman Max Baucus, D-Mont., said, noting that under the rule the hearing could not continue past noon.

The rule about committee meeting times is obscure, but it does surface from time to time. A recent notable example was this past May, when Republicans declined to consent to the Health, Education, Labor and Pensions Committee's consideration of Thomas E. Perez to be Labor secretary.

Senators spent most of their morning away from the hearing room because they had a series of procedural votes on the floor, starting with confirmation of Patricia Ann Millett to the D.C. Circuit Court of Appeals and a series of motions that will lead to confirmation of Rep. Melvin Watt, D-N.C., to head the Federal Housing Finance Agency, quite possibly by the end of business Tuesday.

Republicans required roll call votes on several procedural items that might ordinarily have been handled by unanimous consent until Democrats changed the precedent on nominations to eliminate the ability of the minority party to sustain a filibuster. During the vote sequence, Minority Leader Mitch McConnell of Kentucky sought to overturn the precedent that set up the simple majority threshold, effectively trying to undo the "nuclear option."

The Senate turned back McConnell's procedural appeal, 51-45.

The use of the two-hour rule on a routine nomination hearing is telling. It's a signal that Senate Republicans are in no mood to allow Majority Leader Harry Reid, D-Nev., much schedule flexibility under the revised Senate rules.

"We will reconvene at the earliest possible time, given the complexities and special rules of the Senate," Baucus said. "And I again regret that we cannot continue the hearing now, but we will resume the hearing at the appropriate time. But I cannot resume the hearing after this next vote which is occurring right now because ... the Republican Party has said, which is their right, that the Senate hearings cannot continue two hours after the Senate comes into session."

This follows Monday evening's exchange on the Senate floor between Reid and Sen. Lamar Alexander, R-Tenn., about the rules, during which Alexander pledged to have standing objections "until I understand better how a United States senator is supposed to operate in a Senate without rules."